Hollow floating shaft for clamshell bucket



Jan. 27, 1970 H. P. YAUN 3,491,468

HOLLOW FLOATING SHAFT FOR CLAMSHELL BUCKET Filed Aug 23, 1966 2 Sheets-Sheet 1 INVENTOR HUE') YAUN ATTORNEYS United States Patent 3,491,468 HOLLOW FLOATING SHAFT FOR CLAMSHELL BUCKET Huey P. Yaun, Baton Rouge, La., assignor to Yaun Mauufacturing Co., Inc., a corporation of Louisiana Filed Aug. 23, 1966, Ser. No. 574,344 Int. Cl. B66e 3/02 US. Cl. 37184 10 Claims ABSTRACT OF THE DISCLOSURE A clamshell bucket in which a lower sheave block, by a center shaft assembly, supports a pair of bucket elements and an upper sheave block, through link operating members is attached to the ends of the bucket element by corner bracket assemblies; the center shaft assembly includes a hollow floating shaft on which are rotatably mounted, by bushings, spaced center, inner and Outer hub members; lubricant is fed to the spaces between the bushings from the hollow shaft and is prevented from escape therefrom by a magnetic duo-cone seal means; the corner bracket assemblies are each similar in construction to the center shaft assembly.

The present invention relates to clamshell buckets and particularly to (a) an improved center shaft assembly and (b) an improved main hub assembly for clamshell buckets used, generally, in excavating or in the handling of materials, such as coal, ore or sand.

The need for such improvement arises because of the conditions that exist in the environment where clamshell buckets are ordinarily employed and because of the nature of the materials that they handle. Due to both, the nature of the surroundings and the materials handled, sand, grit and water find their way between the movable parts of the clamshell bucket. This results in a rapid deterioration of such parts, a loss in operating efiiciency and ultimately a complete breakdown of the clamshell bucket.

Experience has made it apparent that the loss in time that the clamshell bucket is out of service during replacement of worn parts is not only inconvenient but also expensive. Thus, the need for a simple, efficient and relatively inexpensive center shaft assembly and a simply, etficient and relatively inexpensive main hub assembly is evident.

With the foregoing in mind, it is, therefore, the objects of the present invention to provide an improved center shaft assembly and an improved main shaft assembly for a clamshell bucket, which assemblies will not be subject to rapid deterioration previously encountered in assemblies of this type.

A still further object hereof is to provide a device conforming with a preceding primary object wherein the wearing parts of the center shaft assembly of a clamshell bucket are durable, simple and of inexpensive construction.

Yet another object hereof is to provide a device conforming with a preceding primary object wherein the wearing parts of the main hub assembly of a clamshell bucket are durable, simple and of inexpensive construction.

The invention will be better understood, and objects other than those set forth above, will become apparent after reading the following detailed description thereof. Such description refers to the annexed drawings presenting preferred and illustrative embodiment of the invention.

In the drawings:

FIGURE 1 is a side view of a clamshell bucket showing the center shaft assembly and main hub assembly;

3,491,468 Patented Jan. 27, 1970 ice FIGURE 2 is an end view of the clamshell bucket;

FIGURE 3 is a sectional view of the center shaft assembly, taken along the line 33 of FIGURE 1;

FIGURE 4 is a sectional view, taken along line 4-4 of FIGURE 3;

FIGURE 5 is an enlarged detail showing in section a sealing means; and

FIGURE 6 is a sectional view, taken along the line 6-6 of FIGURE 1.

Referring to FIGURE 1, it is to be noted that the clamshell bucket includes a conventional upper sheave block 10, and a conventional lower sheave block 12. The lower sheave block 12 supports, by means of a center shaft assembly 16, a pair of bucket jaws 18, 18'. Each of these bucket jaws 18, 18' are provided with teeth 20. The teeth on each bucket jaw are preferably arranged to overlap the other bucket jaw when the bucket jaws of the clamshell bucket are in closed position.

Each clamshell bucket is provided with a pair of spaced ends 22 and 24, respectively, and each of the ends 22, 24, which are located adjacent each other on different buckets, lie in a common place.

Secured to the ends of clamshell bucket jaws 18, by any conventional means, such as welding or riveting, are hinge pieces 26, 26'. Similarly, secured to the respective ends of clamshell bucket jaw 18 are hinge pieces 28, 28'.

The terminal portions of hinge pieces 26, 26' lie closely adjacent each other. In a like manner, the terminal portions of hinge pieces 28, 28' lie closely adjacent each other, but in substantially spaced relation with respect to the terminal portions of hinge pieces 26, 26'.

The terminal portions of the hinge pieces are supported by a center shaft assembly indicated, generally, as 16 in FIGURE 3,

The center shaft assembly 16 includes a center hub 30 supported by the lower sheave block 12. The center hub 30 is provided with open ends, one of which is shown at 32 in FIGURE 3. A center hub bushing 34 is provided in each open end of the center hub 30. A hollow shaft 36 extends through the bushings 34 with the'outboard ends of the shaft extending beyond such bushings. At the extreme outer ends of the shaft 36, a bushing 38 is floatingly mounted. Spaced between the outer end of each bushing 34 and the inner end of each bushing 38, there is floatingly mounted on shaft 36, a further bushing 40.

An inner hub 42 is mounted on each bushing 40 with its inner end in closely spaced relation to the outer end of center hub 30. Similarly, an outer hub 44 is mounted on each bushing 38 with its inner end in closely spaced relation to the outer end of each hub 42.

The outer end of each outer hub has mounted thereon in any conventional manner means to seal in fluid tight relation the outer end of said outer hub. Such means may be, for example, an end cap 46 secured to outer hub 44 by welding.

In order to seal the spaces which occur between the ends of the center hub 30 and the inner end of each innet hub 40, as well as the spaces between the outer end of each inner hub 42 and the inner end of each outer hub 44, magnetic duo-cone seal means 48 are provided.

Each of these magnetic duo-cone sealing means 48 comprise a pair of O-ring seal suports 50, 50 disposed on opposite sides of each of the spaces formed between the hubs. The O-ring seal suports 50, 50' are provided with faces 52, 52 which oppose each other and are machined to a micro inch finish and then magnetized. By reason of their magnetization, the machined faces 52, 52' are attracted to each other and form a magnetic seal therebetween.

The O-ring seal supports 50 and 50 are, respectively, provided with O-rings 54, 54 which are situated on op- 3 posite sides of each of the spaces formed between the hub members 30, 40 and 42 and in sealing contact with the hub members.

The hollow floating shaft 36 is provided with passages 56 which extend from the interior 58 of the hollow shaft 36 to space 60 between the exterior of the hollow shaft and the interior of the center hub 30. Passages 56 are also provided between the interior 58 of the hollow shaft and the spaces between the bushings. The center hub 30 is provided with a threaded plug 62. Upon removal of plug 62, lubricant material, such as oil, may be supplied to the interior 58 of the hollow floating shaft 36, the space 60 between the hollow floating shaft 36 and the center hub 30, and the spaces between the bushings. Leakage of the lubricant material through the spaces between the hubs is prevented by the combined magnetic and O-ring seals.

The clamshell bucket jaws 18, 18' are opened and closed by the operation of the upper sheave block 12. Removably attached to each of the bucket ends 22, 24 by securing means, preferably bolts 64, are corner bracket assemblies, indicated, generally, by the numeral 66. The corner bracket assemblies 66 each include a main hub 68 to which is secured, by welding or other conventional means, arm brackets 70. Extending from the upper sheave block 12 and removably attached to each arm bracket 70 by bolts 72 are link members 74.

The corner bracket assemblies 66 each include a base plate 76 having a pair of spaced parallel outwardly extending flange members 78. Each of the flange members 78 is preferably provided with a circular opening 80. Spaced cap plates 84 extend through the openings 80 and are secured to the flange members 78 by bolts 82, or other suitable connection means. Each spaced cap plate 84 includes a tubular portion 85 and mounted in the tubular portion 85 is a bushing 86. The bushings 86 serve to floatingly support a hollow shaft 88. A pair of bushings 90 are floatingly mounted on hollow shaft 88 in spaced relation to bushings 86 and to each other. The main hub 68 is rotatably supported on bushings 90 and has its ends positioned in closely spaced relation to the ends of tubular portion 85 of cap plates 84.

The spaces formed between the ends of the main hub 68 and the tubular end portions 85 of members 84 are sealed by magnetic duo-cone seals 92 having the same construction as the magnetic duo-cone seals illustrated in FIGURE 5.

The hollow shaft 88 is provided with passages 94 which extend from their interior of hollow floating shaft 88 to the space 96 between the exterior of the hollow shaft 88 and the interior main hub 68. Passages 94 are also provided between the interior of the hollow shaft 88 and the spaces adjacent bushings 86, 90. The main hub is provided with a threaded plug 98. Upon removal of plug 98 lubricant material, such as oil, may be supplied to the interior of the hollow floating shaft 88, the space between the exterior of the hollow floating shaft 88 and the interior of the main hub 68, and the spaces adjacent bushings 86, 90.

With a clamshell bucket constructed so as to include the improved center shaft assembly and/or main hub assembly, it is apparent that the movable parts of such assemblies will be protected against abnormal wear and deterioration due to the entrance of sand, grit or water into the spaces between such movable parts. Moreover, the provision of the hollow shaft construction not only results in a saving of material, but because of its lighter Weight, wear between the movable parts is substantially reduced. Further, the space formed by such hollow shaft construction serves as a lubricant material storage chamber thereby materially decreasing the frequency that the clamshell bucket requires lubrication servicing.

After reading the foregoing detailed description, it will be apparent that the objects set forth above initially have been successfully achieved. Accordingly:

What is claimed is:

1. A hollow floating shaft assembly comprising a center hub having Open ends; center hub bushings, one mounted in each of said open ends; a hollow shaft floatingly supported by said center hub bushings and extending therethrough and outwardly beyond said open ends; an outer bushing floatingly mounted on and adjacent to each end of said hollow shaft; an inner bushing floatingly mounted on said hollow shaft between each outer bushing and an adjacent center hub bushing; outer and inner hubs mounted, respectively, on said outer and inner bushings; each of said inner hubs having an inner end disposed in close proximity to an adjacent end of the center hub; the inner end of each outer hub being closely spaced with respect to the outer end of an adjacent inner hub; an end cap secured to and closing the outer end of each outer hub; means sealing the spaces formed between the ends of the central hub and the inner ends of the inner hub; means sealing the spaces formed between the outer end of the inner hub and the inner end of the outer hub; passage means extending through said hollow floating shaft located to establish communication between the interior of said hollow shaft and the interior of said center hub and between the hollow shaft and the spaces between said bushings; and lubricant material filling the interior of the center hub, the hollow shaft and the spaces between said bushings.

2. A floating shaft assembly as in claim 1 wherein said space sealing means each comprise a pair of O-ring seal supports disposed on opposite sides of said spaces and O-ring seals carried by said seal supports.

3. A floating shaft assembly as in claim 2 wherein said seal supports have magnetized faces attracted to form a seal therebetween.

4. A floating shaft assembly as in claim 1 wherein said sealing means comprise elements having magnetized faces attracted to form a seal therebetween.

5. A hollow floating shaft assembly comprising a central tubular member having open ends; a pair of bushings, one mounted in each of said open ends; a hollow shaft floatingly supported by said bushings and extended therethrough and outwardly beyond said central tubular member open ends; an additional bushing means floatingly mounted on said hollow shaft outwardly of each bushing of said pair of bushings, tubular means mounted on each said additional bushing means and having an inner open end and a closed outer end; the inner open end of each of said tubular means being disposed adjacent and directed toward an open end of said central tubular member; means sealing the spaces formed between each open end of said central tubular member and the inner end of said tubular means; first passage means extending through said hollow floating shaft connecting the space between said pair of bushings with the interior of said hollow floating shaft; second passage means extending through said hollow floating shaft connecting the interior of said hollow floating shaft and each of the spaces between a respective one of said pair of bushings and associated bushing means, and lubricant material filling the interior of said hollow floating shaft and the spaces between respective ones of said pair of bushings and associated ones of said bushing means.

6. A corner bracket assembly comprising a base plate and outwardly directed flanges each having a circular opening therein, a pair of longitudinally spaced cap plates having a tubular portion extending therefrom, respectively mounted on said flanges with said tubular portions extending into said circular openings; cap plate bushings mounted on said cap plates a hollow shaft floatingly carried by said cap plate bushings; a main hub; spaced bushings supporting said main hub on said hollow shaft; sealing means sealing the spaces between the cap plates and said main hub; said hollow shaft being provided with passage means to cause lubricant to fill a closed chamber defined by said cap plates, said main hub and seal means;

and lubricant material filling said hollow shaft and said closed chamber.

7. A corner bracket assembly as in claim 6 wherein said space sealing means each comprise a pair of O-ring seal supports disposed on opposite sides of said spaces and O-ring seals carried by said seal supports.

8-. A corner bracket assembly as in claim 7 wherein said seal supports have magnetized faces attracted to form a seal therebetween.

9. A corner bracket assembly as in claim 6 wherein said sealing means comprise elements having magnetized faces attracted to form a seal therebetween.

10. A clamshell bucket comprising an upper sheave block; a lower sheave block; a pair of bucket jaws, each having teeth thereon and spaced ends, the teeth on each bucket jaw being arranged to overlap the other bucket jaw when the bucket jaws are closed; a first pair of hinge pieces each having terminal portions located closely adjacent each other extending from first adjacent ends of a pair of bucket jaws; a second pair of hinge pieces, each having terminal portions located closely adjacent each other extending from second adjacent ends of said pair of bucket jaws; the terminal portions of the first pair of hinge pieces being spaced from the terminal portions of the second pair of hinge pieces; a center shaft assembly supporting said hinge piece terminal portions comprising a center hub supported by said lower sheave block having longitudinally spaced open ends; a center hub bushing located within each center hub open end; a hollow shaft extending floatingly through and beyond said center hub bushings; an outer bushing floatingly mounted on and adjacent to each end of said hollow shaft, an inner bushing floatingly mounted on said hollow shaft between each outer bushing and an adjacent center hub bushing; outer and inner hubs mounted, respectively, on said outer and inner bushings; each of said hubs having inner and outer ends, the inner end of each inner hub being disposed adjacet and directly toward the adjacent end of the center hub; the inner end of each outer hub being disposed adjacent and directly toward the outer end of each inner hub; an end cap welded to and closing the outer end of each outer hub; magnetic duo-cone seal means sealing the spaces formed between the ends of the central hub and the inner ends of the inner hub, magnetic duo-cone sealing means sealing the spaces between the outer end of the inner hub and the inner end of the outer hub, each said magnetic duo-cone sealing means comprising a pair of O-ring seal supports disposed on opposite sides of said spaces having magnetized faces attracted to form a seal therebetween and O-ring seals carried by said seal Supports and cooperating with the hubs between which the spaces are formed to seal said spaces; passages extending through said hollow shaft located to establish communication between the interior of said hollow shaft and the interior of said center hub and between the hollow shaft and the spaces between said bushings; lubricant material filling the interior of the center hub, the hollow shaft and the spaces between said bushings; means for opening said bucket jaws comprising corner bracket assemblies detachably connected to upper portions of the bucket jaws and link members connected to said upper sheave block; said corner bracket assemblies including a corner bracket, a pair of longitudinally spaced cap plates mounted on said corner bracket; cap plate bushings mounted in said cap plates, a hollow shaft floatingly carried by said cap plate bushings; a main hub; spaced bushings supporting said main hub on said hollow shaft; magnetic duo-cone seal means sealing the spaces between said cap plates and said main hub; said corner bracket, said cap plates, said main hub and said magnetic duo-seals coacting to form a closed chamber; and lubricant material filling said closed chamber; and arm bracket plates and bolts removably secur ing said main hub to said link members.

References Cited UNITED STATES PATENTS 777,500 12/1904 Fickinger et a1. 37188 1,541,064 6/1925 Norris 37-4 4 1,644,743 10/1927 Norris 37 84 1,686,176 10/1928 Robin et a1 37-184 1,864,793 6/1932 Botten 37184 2,614,006 10/1952 Bechrnan 30836.1 XR 2,639,172 5/1953 Leonard 641 XR 2,647,772 8/1953 Wernert 30836.1 XR 3,135,111 6/1964 Roe 30837 XR 3,239,285 3/1966 Madeira et al. 30836.1 XR

FOREIGN PATENTS 879,754 10/1961 Great Britain.

EDGAR S. BURR, Primary Examiner US. or. X.R, 64- -1; sou-36.1, 37, 87 

